Conventionally, attempts have been made to detect a cut point as a change in scene (cutaway) included in a moving image, and to form indices which are used to browse and search the moving image. Upon detecting a cut point, if a flash-emitted frames (flash portion) is inserted, it is erroneously detected as a cut point, and some solutions to this problem have been proposed. In Japanese Patent No. 2,839,132, an inter-frame distance table is prepared for all combinations of three or more frames, a scene change ratio is computed based on the inter-frame distance table, and if the frame change ratio is equal to or higher than a threshold value, a cut point is determined. In Japanese Patent Laid-Open No. 10-224741, as for a frame N of interest and its previous and next frames (N−1) and (N+1), if N and (N−1) have a low correlation value, and (N−1) and (N+1) have a high correlation value, N is determined to be a flash portion, and is excluded from frames from which a cut point is to be detected. Also, as for the frame N of interest and its previous and next frames (N−1), (N+1), and (N+2), correlation values between N and (N−1), (N+1) and (N−1), and (N+2) and (N−1) are computed. If N and (N−1), and (N+1) and (N−1) have low correlation values, and (N+2) and (N−1) have a high correlation value, N and (N+1) are determined to be flash portions, and are excluded from frames from which a cut point is to be detected.
However, the method of Japanese Patent No. 2,839,132 must obtain inter-frame distances for all combinations of three or more frames. To obtain higher precision, inter-frame distances of more frames must be computed, resulting in higher computation cost. Also, the scene change ratio must also be computed, and the computation cost is high. On the other hand, in Japanese Patent Laid-Open No. 10-224741, a number of computation of inter-frame distance is little, and the computation cost is low. However, e.g., a press conference in a news movie, since a plurality of cameras emit flash light many times, three or more frames included by the flash light may continue. However, the above method can only cope with a case wherein two frames influenced by flash light continue, resulting in poor precision.